Domain name resolution issues break DefaultConnectionPool when using getAsync

JAVA-3690

Author: jstewart148

driver-core/src/main/com/mongodb/connection/netty/NettyStream.java

@@ -106,7 +106,16 @@ public void open() throws IOException {
 
     @Override
     public void openAsync(final AsyncCompletionHandler<Void> handler) {
-        initializeChannel(handler, new LinkedList<SocketAddress>(address.getSocketAddresses()));
+        Queue<SocketAddress> socketAddressQueue;
+
+        try {
+            socketAddressQueue = new LinkedList<SocketAddress>(address.getSocketAddresses());
+        } catch (Throwable t) {
+            handler.failed(t);
+            return;
+        }
+
+        initializeChannel(handler, socketAddressQueue);
     }
 
     private void initializeChannel(final AsyncCompletionHandler<Void> handler, final Queue<SocketAddress> socketAddressQueue) {

driver-core/src/main/com/mongodb/internal/connection/AsynchronousSocketChannelStream.java

@@ -55,7 +55,16 @@ public AsynchronousSocketChannelStream(final ServerAddress serverAddress, final
     @Override
     public void openAsync(final AsyncCompletionHandler<Void> handler) {
         isTrue("unopened", getChannel() == null);
-        initializeSocketChannel(handler, new LinkedList<SocketAddress>(serverAddress.getSocketAddresses()));
+        Queue<SocketAddress> socketAddressQueue;
+
+        try {
+            socketAddressQueue = new LinkedList<SocketAddress>(serverAddress.getSocketAddresses());
+        } catch (Throwable t) {
+            handler.failed(t);
+            return;
+        }
+
+        initializeSocketChannel(handler, socketAddressQueue);
     }
 
     private void initializeSocketChannel(final AsyncCompletionHandler<Void> handler, final Queue<SocketAddress> socketAddressQueue) {

driver-core/src/test/functional/com/mongodb/connection/netty/NettyStreamSpecification.groovy

@@ -1,14 +1,17 @@
 package com.mongodb.connection.netty
 
 import category.Slow
+import com.mongodb.MongoSocketException
 import com.mongodb.MongoSocketOpenException
 import com.mongodb.ServerAddress
+import com.mongodb.connection.AsyncCompletionHandler
 import com.mongodb.connection.SocketSettings
 import com.mongodb.connection.SslSettings
 import org.junit.experimental.categories.Category
 import spock.lang.IgnoreIf
 import spock.lang.Specification
 
+import java.util.concurrent.CountDownLatch
 import java.util.concurrent.TimeUnit
 
 import static com.mongodb.ClusterFixture.getSslSettings
@@ -64,4 +67,43 @@ class NettyStreamSpecification extends Specification {
         then:
         thrown(MongoSocketOpenException)
     }
+
+    @IgnoreIf({ getSslSettings().isEnabled() })
+    def 'should fail AsyncCompletionHandler if name resolution fails'() {
+        given:
+        def serverAddress = Stub(ServerAddress)
+        def exception = new MongoSocketException('Temporary failure in name resolution', serverAddress)
+        serverAddress.getSocketAddresses() >> { throw exception }
+
+        def stream = new NettyStreamFactory(SocketSettings.builder().connectTimeout(1000, TimeUnit.MILLISECONDS).build(),
+                SslSettings.builder().build()).create(serverAddress)
+        def callback = new CallbackErrorHolder()
+
+        when:
+        stream.openAsync(callback)
+
+        then:
+        callback.getError().is(exception)
+    }
+
+    class CallbackErrorHolder implements AsyncCompletionHandler<Void> {
+        CountDownLatch latch = new CountDownLatch(1)
+        Throwable throwable = null
+
+        Throwable getError() {
+            latch.countDown()
+            throwable
+        }
+
+        @Override
+        void completed(Void r) {
+            latch.await()
+        }
+
+        @Override
+        void failed(Throwable t) {
+            throwable = t
+            latch.countDown()
+        }
+    }
 }

driver-core/src/test/functional/com/mongodb/internal/connection/AsyncSocketChannelStreamSpecification.groovy

@@ -1,8 +1,10 @@
 package com.mongodb.internal.connection
 
 import category.Slow
+import com.mongodb.MongoSocketException
 import com.mongodb.MongoSocketOpenException
 import com.mongodb.ServerAddress
+import com.mongodb.connection.AsyncCompletionHandler
 import com.mongodb.connection.AsynchronousSocketChannelStreamFactoryFactory
 import com.mongodb.connection.SocketSettings
 import com.mongodb.connection.SslSettings
@@ -11,6 +13,7 @@ import spock.lang.IgnoreIf
 import spock.lang.Specification
 
 import java.nio.channels.AsynchronousChannelGroup
+import java.util.concurrent.CountDownLatch
 import java.util.concurrent.Executors
 
 import static com.mongodb.ClusterFixture.getSslSettings
@@ -70,4 +73,44 @@ class AsyncSocketChannelStreamSpecification extends Specification {
         then:
         thrown(MongoSocketOpenException)
     }
+
+    @IgnoreIf({ getSslSettings().isEnabled() })
+    def 'should fail AsyncCompletionHandler if name resolution fails'() {
+        given:
+        def serverAddress = Stub(ServerAddress)
+        def exception = new MongoSocketException('Temporary failure in name resolution', serverAddress)
+        serverAddress.getSocketAddresses() >> { throw exception }
+
+        def stream = new AsynchronousSocketChannelStream(serverAddress,
+                SocketSettings.builder().connectTimeout(100, MILLISECONDS).build(),
+                new PowerOfTwoBufferPool(), null)
+        def callback = new CallbackErrorHolder()
+
+        when:
+        stream.openAsync(callback)
+
+        then:
+        callback.getError().is(exception)
+    }
+
+    class CallbackErrorHolder implements AsyncCompletionHandler<Void> {
+        CountDownLatch latch = new CountDownLatch(1)
+        Throwable throwable = null
+
+        Throwable getError() {
+            latch.countDown()
+            throwable
+        }
+
+        @Override
+        void completed(Void r) {
+            latch.await()
+        }
+
+        @Override
+        void failed(Throwable t) {
+            throwable = t
+            latch.countDown()
+        }
+    }
 }